1. Field of the Invention
The present invention relates to a curtain wall system, specifically an improved system and method of erecting the curtain wall system.
2. Description of the Related Art
The typical panel erection method of an enhanced curtain wall (CW) system as generally described by Ting in U.S. Pat. No. 7,134,247 starts erecting the panels near the bottom of a building (i.e., a bottom-up process) and includes the following steps:                (1) placing a panel into an engaged position with two, generally vertical supporting mullions and sliding the panel downwardly into engagement with a previously erected panel below;        (2) fastening the upper frame segment of the panel with two panel fasteners to the adjacent mullions; and        (3) engaging a panel water seal and a rain screen member to the upper frame segment.        
It should be noted that one of the advantages of the above-mentioned enhanced curtain wall system is the absence of horizontal mullions. The lack of horizontal mullions simplifies the erection method and minimizes costs.
In new or renovation curtain wall (CW) construction in a downtown area, e.g., due to the limited available space for construction traffic, it is desirable to enclose the first floor last, necessitating top-down panel erection methods for the panels above the first floor. Also, a top-down renovation method allows immediate re-occupancy of a renovated floor, prevents water and/or construction debris from falling into a renovated lower floor, and avoids construction traffic going through a renovated lower floor to an upper floor undergoing renovation.